There is a case that physical quantities such as velocity and pressure distributions of resin material, that is molten and plasticized by rotating a screw provided in an extruder or an injection molding device, is calculated, and then prediction of a molding process such as prediction of physical properties of a kneaded state and velocity and pressure distributions, etc. is performed. In this case, analysis software using an analysis method such as an FAN method (Flow Analysis Network Method) or an FEM (finite element method) is generally employed.
The FAN method is representatively described in Japanese Patent No. 3,679,392, Japanese Patent No. 4,414,408 and JP-A-09-029819. According to the FAN method, for example, in a case of using an extruder as an analysis object, distribution states of a fill factor, a pressure, a temperature, a solid-phase occupancy, a residence time, a torque, a power, etc. within the extruder are arithmetically predicted as respective average values in a cross-section along the axial direction of the extruder, based on a device configuration, an operation condition and physical properties of material of the extruder. As simulation softwares on the market using this method, there are known, for example, “TEX-FAN” developed by Japan Steel Works, Ltd., “EXTRUCAD” and “NEXTRUCAD” developed by PolyDynamics INC., “WinSSD” of Polymer Processing Institute, “REX” of Paderborn University in Germany and “EXTRUDER” of Compuplast, and “AKRO-CO-TWIN SCREW” developed by Akron University in the United States.
According to the FAN method, for example, in a case of using an extruder as an analysis object, a flow path existing between a screw and a cylinder of the extruder is cut along a circumferential direction of the cylinder and thus modeled into two plates, that is, upper and lower plates respectively corresponding to the cylinder wall surface and the screw surface. In a state that these two plates are arranged to have an interval of a groove depth of the screw, a fluid flow state is arithmetically operated under a condition that the plate corresponding to the screw surface is translated by a distance corresponding to a rotation speed of the screw. In this method, in a case of noticing an element at a certain cross-section of the flow path, a fluid pressure, a residence time and a fluid flow rate flowing to the downstream side, etc. within this element can be calculated by solving a balance between a flow rate of the fluid (resin material in a molten state) flowing from the upstream side and a conveying amount of the fluid provided by the element itself. By sequentially executing this calculation with respect to the flow-path element from the upstream side to the downstream side or vice versa, physical quantities of the entire extruder can be calculated finally. In this manner, as the physical quantities in the axial direction of the entire extruder are outputted, this method is considered as an one-dimensional analysis (1D analysis).
In contrast, according to the FEM, a flow path as an analysis object is entirely divide into lattice elements, then nodes within the elements are set as calculation points, then the law of conservation of mass and the law of conservation of momentum is discretely applied to each of all the nodes, and physical quantities of the entire flow path can be calculated by solving a simultaneous equation for each of the calculation points. Thus this method is considered as a kind of a lattice element method. As the lattice element method, another method such as an FVM (finite volume method) or an FDM (finite difference method) is applied in place of the FEM, depending on software. As an analysis of an extruder using the methods, there is known a case achieved by the research team of Kyushu University represented by K. Funatsu, S. Kihara, M. Miyazaki, S. Katsuki and T. Kajiwara, Polym. Eng. Sci., 42, 707 (2002). As general-purpose softwares, for example, “POLYFLOW” of ANSYS Inc. and “SCREWFLOW-MULTI” of R-flow Corporation Ltd. are known. A fluid-flow analysis according to this method is implemented to a two-dimensional (2D) analysis or a three-dimensional (3D) analysis. In particular, due to remarkable improvement in efficiency of computer hardware in recent years, this method is applied to a 3D analysis in general.
Concerning the analysis according to the FAN method and the FEM, as the FAN method can obtain physical quantities in the axial direction of an entire area of an extruder, this method is often used in order to grasp transition tendency of physical properties of resin within an extruder or to predict quality of the extrusion resin. In contrast, as the FEM can hardly perform prediction of an entire area of an extruder even under a current environment of computer efficiency. Thus, the FEM is mainly used in order to perform prediction of a two-dimensional cross-section of a kneaded portion or to extract a kneaded area three-dimensionally and perform a 3D analysis, thus predicting a detailed fluid-flow state of thus locally extracted area.
However, respective analysis software using the FAN method and the FEM as described above is applied to respective characteristic analyses, that is, respective analyses matched to information required by a user. Thus, an integrated analysis incorporating merits of the both methods cannot be realized by single software. In other words, it is impossible to simultaneously implement both a low-dimensional analysis such as the 1D analysis and a high-dimensional analysis such as the 3D analysis based on the same software. Accordingly, in a case of performing both a low-dimensional analysis and a high-dimensional analysis under the same operation conditions of an extruder, firstly parameters are set manually so that the operation conditions become the same between the respective software. Then outputted results from the respective software are classified separately. In this manner, finally an analysis executor is required to obtain physical quantity evaluation of resin in the entirety of an extruder and also evaluation of local kneading behavior, by classifying and processing outputted data from the respective software separately. Such a work is very complicated.